Laboratory experiments were conducted to evaluate the potential for in situ biodegradation in the contaminated groundwater aquifer at the Hoe Creek underground coal gasification site. Experiments were performed in electrolytic respirometric cells under simulated environmental condition. An orthogonal, fractional factorial design was used to evaluate the effects of the following factor on phenol degradation: nutrient dose, amount of bacterial inoculum, temperature, light conditions, and substrate concentration. Microorganisms native to the environment were used as the inoculm, and phosphorus was used as the nutrient.